Configuring and Using Backup Devices

Using Several Drive Types in a Library

 

Using Several Drive Types in a Library

 

Using several drive types of a similar technology like DLT

 

4000/7000/8000 (the same is true within the DDS family) in the same

 

library can lead to problems when you use the media in any drive, but do

 

not ensure a common format on all media.

 

For example, at restore time, a DLT 4000 cannot read a tape that has

 

been written with a DLT 8000 (highest density). Compressed and

 

non-compressed media cannot be used interchangeably.

 

To avoid these kind of problems, you can either use a common density

 

setting for all your media, or you can separate your media pools. Both of

 

these solutions are described in the following sections.

Same Density

This method uses a common format on all media, which allows you to use

Setting

all media interchangeably in any drive.

 

For devices used on Windows systems, consult the drive documentation

 

for information about using a specific write density.

 

On UNIX systems, you can set the density for drives by selecting the

 

related device filenames and using them in the device definitions. The

 

density must be set at the same value. For example, in case of DLT 4000

 

and DLT 7000 drives, the DLT 4000 drive density should be set.

 

Make sure the block size setting of the devices used is the same. This

 

setting in the device definition must be used at the time the media are

 

formatted.

 

The free pool concept can be used as desired.

 

During a restore, any drive can be used with any media.

 

On HP-UX, you can set the density of a drive when creating the device

 

filename. See Appendix B, “Creating the Device Files on HP-UX”, in the

 

HP OpenView Storage Data Protector Installation and Licensing Guide

 

for more information.

Different Media

This method separates the media used by one group of drives from the

Pools (on UNIX

media used by another group of drives, allowing you to better optimize

and Windows)

drive and media usage.

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Chapter 2